Art of treating photographic surfaces



April 9, `1935. v. A. STEWART ART 0F TREATING PHOTQGRPHIC SURFACES Filed Oct. 3l, 1931 INVENTOR www KM/J ATTORNEY4 Patented Apr. 9, 1935 A UNITED lSTATES .PATENT oFFlcE nar oF TnEA'rnvG PnoToGnAPnIc simmons Victor A. Stewart, New York, N.l Y., asslgnor to Louis A. Solomon', New York, N. Y., as trustee Application october s1, 1931, serial No. 572,423

v claims. (c1. en -ss) My invention relates to a solution for treating' The solution which I employ for treating the photographic surfaces, more vspeciically cinematfilm contains three principal ingredients, namely, ographic films, and to the process of treating formaldehyde, tannic acid and glycerine, in adthe lms with such solution. i dition to certain others. I am aware that these The principal object of the invention is to three ingredients have been used heretofore in 5 harden and toughen the film, thereby improving the treatment of photographic surfaces, but I its properties and lengthening its useful life believe that these substances have been used greatly beyond what is at present considered either separately, each for itself, or two together normal. and that I am the rst/to use all three in one High speed vprojection of cinematographic solution. By treating iilms with a solution conl0 p films, which is common practice, tends to injure taining the three ingredientsI obtain a product and wear the film in a short time, necessitating greatly superior in clarity, toughness with exifrequent repair and replacement at relatively bility, absence of streakiness and length of useful short intervals. As a consequence, the cost of life, to any film which has been treated with 415 lms is increased and much labor and other inonly one or with any two of the three vin-r l byrst winding the exposed and developed iilm the scope thereof.

conveniences follow in train. gredients.

In my prior Patent 1,569,151 granted January The following example is given to illustrate 12, 19 I disclose a method of rendering the lcola' practical embodiment. of the 'solution of my loid su stance or emulsion of the film insoluble invention, but is not to be taken as limitative of 20 together with`a porous spacing material into a Mix together in the order named at room temcomposite roll and then subjecting the lm tol the perature and with constant stirring, one quart of vaction of chemical vapors in a gas tight chamber. water, one quart formaldehyde, one ounce tannic This method is highly effective for its intended acid, three ounces glycerine, two quarts turpen- V purpose; however, -it involves winding the iilm tine, one-quart eucalyptus oil, three quarts car- 25 onto a reel with a porous material interposed bon tetrachloride and suiiicient alcohol for the between the lmconvolutions. placing the asmiscibility of the oil and water. The quantities sembly in a gas tight chamberv for the lvapor of the ingredients used may be varied within tlatment, removing the assembly and rewinding suitable limits and Acertain of the ingredients,

the ilm, without the interposed material, onto a other than those indicated above as being essen- 30 new reel. These several steps are time consumtial, may be entirely omitted. 'I'he formaldehyde ing and also involve expense. The us'e of the acts to harden the emulsion, preserve it from interposed fibrous material .is necessary to keep decay and render it more permanent and resistthe 'surfaces of the nlm convolutions from adherant to mechanicaldisintegration; the tannic acid ing to each other and to permit the vapors to toughens the emulsion as distinguished from 35 .have ready access to the gelatinous surface of hardening it; the glycerine is a tempering or softhe film.' y tening agent and aids in rendering the emulsion My present invention reduces the number of. hygroscopic; the turpentine has anoily and bindthe steps involved in the foregoing method by ing eiect to prevent disintegration of the iilm;

'40 eliminating the need for using the fibrous spacing the eucalyptus oil is'a lubricant and the carbon 40 material, the first reeling and the unreelin'g opertetrachloride serves as a solvent forthe oil; the ation and the introduction-of the assembly andv alcohol, as stated above, is to promote the misciits removal from a gas chamber. bility of the oil and Water and it also hastens In accordance with my present invention, the drying of the lm. l lm as it issues from the developing bath is con- In the accompanying drawing, I show purelyL 45 vducted directly to and through the new solution, diagrammatically an installation which may be as hereinafter fully described, and passes thence y used intreating lms with the new solution. I0 to the drying chamber for further usual treatdenotes the' chamber in which :the lm II is ment. It will be apparent Ifrom this brief outdeveloped by any of the usual wet developers.

` line of operation that the treatment with the As the iilm issues, in undried condition, from 5o new solution is a step which requires no substanthe chamber Ill it is passed into and through the tial time or labor in addition to those required vessel I2 containing the new treating solution. in the usual production of lms and has the added From the vessel I2 the lm is passed .into and advantage that it may be performed as an incithrough the drier I3 in which/ the nlm is fesdent to the normal ccurse of film manufacture, tooned on rolls I4. The film, as it issues from the 56 drier I3, is wound on a. reel IB and is then ready for use. Drip pans I0 may be placed between the developer chamber I0 and the solution vessel l2 and between the latter and the drier i3. The operation is very simple and it will be apparent that the solution treatment of the film is effected in the ordinary course of manufacture of the latter.

I claim:

1. A composition of matter for treating photographic films, comprising formaldehyde, tannic acid and glycerine, in solution.

2. A composition of matter for treating photographic lms, comprising a solution of formalde- 0 hyde, tannic acid, glycerine', a lubricant for the lm and a solvent for the lubricant. l

3. A composition of matter for treating photographic films, comprising a solution of formaldehyde, tannic acid, glycerine, turpentine, eucalyptus oil, carbon tetrachloride and alcohol.

4. A composition of matter for treating photographic lms, comprising a. solution containing a lm hardening substance, a lm toughening substance and a substance for softening the lm and rendering it hygroscopic. i

5. The method of treating photographic lms, comprising submittingA the film to a bath for toughening, hardening and softening the undried developed lm and rendering it hygroscopic.

6. The method of treating photographic lms to render them tough and hard while maintaining their ilexibility, which comprises submitting the lm to a bath containing formaldehyde, tannic acid and glycerine in solution. i 7. The method of treating photographic lms to render them tough and hard while maintaining their flexibility, which comprises submitting the mms to a solution containing a. ilm hardening substance, a ilm toughening substance and a substance for softening the film and rendering it hygroscopic.

VICTOR A. STEWART. 

